Copper's bringing posh Spanish banker in for questioning (7)
I believe the answer is:
curious
'questioning' is the definition.
(similar in meaning)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for curious that I've seen before include "Eager to know something, perhaps nosy" , "Odd or eager to know" , "Eager to know; strange" , "Unusual; eager to learn" , "Odd - inquisitive" .)